Casement windows are well known in the art and are widely used in new constructions. A casement window is hinged at the side and has a window sash which is movably mounted within a frame by a pair of hinges mounted between the window frame at the top and bottom of the window sash. The arrangement is normally one in which a track is mounted to the window frame to interconnect a track and window sash. In this respect, a support arm is pivotably connected to the sash arm and to the track. The sash arm is also pivotably connected to a mounting shoe which is supported and guided for movement lengthwise of the track which is mounted on the window.
An alternative arrangement is to provide an intervening length between the sash arm and the movable shoe to provide for an offset sash arm. Such an arrangement typically includes a second intervening length between the support arm and the movable shoe to provide further support.
An awning window, on the other hand, is pivoted at the top by hinges. Such an arrangement is desirable in certain situations since the window pivots outwardly from the bottom and will remain in a position to shelter or shield the opening.
Casement window operators are also well known in the art. The window operator typically will utilize a hand crank which is rotatable and which in turn drives a worm gear. The worm gear in turn will drive gearing which is connected to the arm which pushes the window sash open. As aforementioned, the worm gear assembly includes a gear shaft having the worm at one end with the other end extending outwardly through the housing to engage the crank.
As described above, there are different opening arrangements for casement windows. A first arrangement utilizes a single arm operator which has an arm which pivots about an axis that is fixed with respect to the window frame and worm gear. A remote end of the arm carries a bearing which slides in a track mounted on the underside of the sash. The known disadvantage of single arm operators is the torque required to move the sash towards its fully open position. Thus, the force required both causes difficulty for the person opening the window and also leads to excessive wear of the mechanism.
A second known type of casement window operator is typically known as a “split arm”. A split arm operator includes a second arm which has a pivot point in the middle of the second arm and the remote end of the second arm is secured through a pivotable mounting to a fixed point on the sash. This arrangement allows the window to extend to its fully open position. However, it does suffer from the disadvantage of requiring excessive force at the time of the initial opening of the sash.
A third type of window operator is typically known as a “dual arm”. The dual arm operator has one arm which rotates about a fixed axis and a housing which carries at its far end a bearing to slide in a track mounted to the window sash. There is also a second arm which has a pivot joint and which is secured at its remote end by a pivotable but fixed connection to the sash.